Tractive device for tractors



Jan. 10, 1939. A 5v BENSQN 2,143,403

TRACTIVE DEVICE FOR TRACTORS Filed June 4, 1935 2 Sheets-Sheet l ATTORNEY$ Patented Jan. 10, 1939 UNITED STATES PATENT OFFlCE 2,143,403 TBACTIVE DEVICE FOR TRACTORS Arthur S. Benson, Seattle, Wash.

Application June 4,

9 Claims.

My present device relates to a 'tractive device for tractors.

There are many purposes 'for which tractors can be used to advantage on rails, such as street railways, or railroad rails. One such use is for switching cars in a switching yard, making up trains, or spotting cars for loading, or unloading. Another field for such a device is for the negotiating of grades which cannot easily be taken tired wheels normally employed on locomotives, rail cars, steam shovels and the like. I

My present device consists of a side slipping block arrangement which, while it might be employed on many types of block tread wheels is particularly adapted for use with caterpillar tractor and it is this use that I have illustrated and particularly described in my following specifications.

I provide means that are adjustable through a wide range so that it can be used on rails having tread head of varying width. I have also provided means for allowing a tractor traveling on two rails to successively negotiate the same even on curves where normally the rails are spread further apart than in straightaways.

The principal object of my present invention is, therefore, to provide a tractive device for tractors that will enable the same to be run on face rails which will guide the tractor on the rails without any aid from the driver; will provide sufficient tractive efforts so that steep grades, or heavy starting loads, can be accomplished and which will so accommodate themselves to rails of varying thickness, and to rails spread to varying degrees, that the tread can be used under all conditions normally met on railway tracks.

Other and more specific objects will be appar ent from the following description taken in connection with the accompanying drawings, wherein Figure l is a side elevation of a portion of a caterpillar tread made after the teachings of my invention showing the same as applied to a rail.

Figure 2 is a bracketed View showing in. exploded perspective view, the parts making up one block unit of my tractive device.

Figure 3 is a side elevation of a tractor belt tread made after the teachings of my invention, certain parts of which are shown in section to better illustrate the construction.

Figure 4 is a cross-sectional view taken along the line 4-4 of Figure 3.

Figure 5 is a similar, sectional view taken along the line 5--5 of Figure 3 and showing the device as applied to a standard rail which also is shown in section.

Referring to the drawings, throughout which like reference characters indicate like parts, 6

1935, Serial No. 24,924

designates my tr-active block. This will probably be best understood from an inspection of Figures 2, 4 and 5. It consists of a slab-like portion 8 and two side portions ill and l I. These side portions are each provided with an inclined inner face as if. and M which have at either end the fixed vertically walled lug l5 and Iii. These are provided with rounded corners at l1 to assist the block in following the rail. Each of the surfaces l2 and it are provided with guideways l8 and is of which there may be one or more under each surface. These guideways accommodate a compression spring 2E3 and guide lugs 2| formed as part of the gripping jaw members 22 and 24. The exact construction of these members will probably be best understood from Figure 2. They consist of the frictional engaging surfaces 26 and overhanging lug members 7.8 which are adapted to engage the top of the rail. Lugs 2i are preferably made with a circular end 30 and a reduced neck portion 35 so that once they are entered into guideways i8 and the cover plate 32 secured place, as by bolt 35, the jaw members are held against being lost as they might be if permitted to drop out of block 6.

Blocks ii are mounted for transverse movement upon base members 35 which are, in turn, fixedly secured to the caterpillar tread members 38, as by a plurality of bolts 33. The exact manner of mounting block 55 on blocks variation. The T-slide arrangement probably best illustrated in Figures 2 and 3, at 46 and 42, provides a very convenient and workable arrangement. These permit block 6 to slide on base and thus be capable of conforming to varying guages of tracks. Their maximum displacement is provided by slot 14 and bolt 45 which act as a limit stop. Normally, however, block 6 moves as a belt being held together in a flexible manner by cables it and at which are continuous throughout the entire belt tread.

Method of use In using my device the usual track plates are is subject to some removed and in place of them the base members 36 are installed, one for each tread plate removed. With most types of tractor treads this will mean one member 35 for each link of the tractor belt. The tread made up of a plurality of blocks 6 which are secured together in a flexi ble and yielding manner by cables GE and 4! is then put in place, being applied from the side and when in about the center of the base members the limit stop screws "it are screwed home. This holds the unit on the normal tractor drive means. The tractor may now be used on ordinary surfaces particularly around yards where they work on planks or on ties and when it is desired to use the same on the rails the treads are centered one over each rail.

In this position the rail top will engage lugs 28 and tend to force jaw members 22 and 24 upvertex of the angle formed by the ina traction-block, of a pair of movable treadplurality of traction blocks pivotally linked together adapted for travel on a rail, the combination with a traction-block straddling the rail comprising a plurality of traction blocks pivotally linked toinoperative positions, and adapted in inoperative position to frictionally engage the rail-head under pressure of weight thereon, each tread-block having a face extendtionally engaged faces diverging downwardly from a point above the longitudinal center of the rail, and springs mounted between said blocks for returning said tread blocks to inoperative position when the load is removed.

means for limiting said movement, of a pair of movable tread-blocks mounted in each traction- ARTHUR S. BENSON. 

